The instant invention relates generally to pumps and, more specificaly, to a vertically orientated turbine pump, and is an improvement on the pump disclosed in my co-pending application Ser. No. 234,589 filed Aug. 22, 1988 entitled "PUMP".
Turbine pumps are often used to move dirty, corrosive or hazardous liquids in, for example, air washers, filtration systems, paint systems, or other chemical systems. Such pumps are taught in, for example, Gschwender Patent No. 4,530,641, which discloses a vertical turbine pump having a pump shaft that is surrounded by lifting ducts which transport the liquid out of the tank. The bearings of Gschwender are lubricated by the liquid being pumped which is then drained back into the tank through clearance gaps in the lifting ducts surrounding the pump shaft. However, if the liquid being pumped contains particulate matter, the bearings may not be properly lubricated. Furthermore, if the liquid is corrosive, the bearings face direct exposure thereto.
U.S. Pat. No. 3,897,176, issued on July 29, 1975, to Emeny discloses a pump having an apertured protective tube surrounding the pump shaft. Liquid flows up the gap between the pump shaft and the protective tube and flows out the apertures of the tube and back down to the impeller area to insure continuous flow. Unfortunately, liquid containing particulate matter may clog the apertures, causing pressurized liquid to flow up the gap and into the shaft bearings.
Modianos U.S. Pat. No. 4,063,849, discloses a vertical turbine pump having a stuffing box subjected to high pressure liquid.
U.S. Pat. Nos. 4,695,222 and 3,478,690 issued on Sept. 22, 1987 and on Nov. 18, 1969, to Barraza and Helke, respectively, disclose selfcontained sewage systems having a pump shaft, a discharge shaft for transport of a liquid, and a protective seal subjected to pressurized liquid. However, neither can be used reliably in applications involving dirty or corrosive liquids because both systems use shaft bearings which may clog or deteriorate if the protective seal leaks during operation.